Class diagrams help you understand the class structure of projects others have written (or that you wrote a long time ago). You can use them to customize, share and present project information with others.
The first step in presenting project information is to create a class diagram that displays what you want to show. For more information, see Viewing Types and Relationships (Class Designer). You can create multiple class diagrams for a project that can be used to display a distinct view of the project, a chosen subset of the project's types, or a chosen subset of the members of types.
As i have also read this thing from msdn so i am pasting that link,you can go through that but according to me its UML which is used to show connectivity and architecture of classes in a project.
http://msdn.microsoft.com/en-us/library/33864ckt.aspx
Thanks & Regards,
Chayan Upadhyay
Naraayanan, if this helps please login to Mark As Answer. | Alert Moderator